Sueki H, Whitaker D, Buchsbaum M, Murphy G F
Department of Dermatology, University of Pennsylvania School of Medicine, Philadelphia.
Lab Invest. 1993 Aug;69(2):160-72.
Dermal dendrocytes are a newly-recognized cell type in human skin. They express coagulation Factor XIIIa (FXIIIa), also known as fibrin stabilizing factor, and their number is increased in certain inflammatory dermatoses. Current dogma suggests that these recently described cells may represent a subset of antigen-presenting macrophages. The present study therefore was undertaken to examine further the phenotype and potential function of these novel cells.
Conventional ultrastructure, single and dual label immunofluorescence and immunocytochemistry, confocal laser scanning microscopy, and immunoelectron microscopy were used to define structure and potential heterogeneity among dermal dendrocytes. Human neonatal foreskin organ culture exposed to mast cell secretagogues, inhibitors, and relevant recombinant cytokines (tumor necrosis factors alpha) was employed to gain insight into functional characteristics of FXIIIa expression.
We found that dermal dendrocytes are phenotypically unique dermal cells, separate from conventional macrophages, with antigenic heterogeneity of FXIIIa and CD34 expression related to their microanatomical location in the dermis. Moreover, they express specialized membrane-matrix plaques that may stabilize their placement in various dermal strata. Finally, superficial subpopulations of dermal dendrocytes are closely-associated with mast cells and show enhanced FXIIIa expression in response to mast cell degranulation, an event that appears to result from liberation of mast cell tumor necrosis factor in the dendrocyte microenvironment.
These new insights establish dermal dendrocytes as distinctive fixed skin cells with potential functional capacity for mast cell-dependent facilitation of fibrin cross-linking and matrix remodeling. These previously unrecognized phenotypic and functional characteristics of dermal dendrocytes therefore may be relevant to cellular interactions responsible for cutaneous wound healing and hemostasis.
真皮树突状细胞是人类皮肤中一种新发现的细胞类型。它们表达凝血因子 XIIIa（FXIIIa），也称为纤维蛋白稳定因子，并且在某些炎症性皮肤病中其数量会增加。目前的观点认为，这些最近描述的细胞可能代表抗原呈递巨噬细胞的一个亚群。因此，本研究旨在进一步研究这些新型细胞的表型和潜在功能。
采用常规超微结构、单标和双标免疫荧光及免疫细胞化学、共聚焦激光扫描显微镜和免疫电子显微镜来确定真皮树突状细胞之间的结构和潜在异质性。用人新生儿包皮器官培养物，使其暴露于肥大细胞促分泌剂、抑制剂和相关重组细胞因子（肿瘤坏死因子α），以深入了解 FXIIIa 表达的功能特性。
我们发现真皮树突状细胞是表型独特的真皮细胞，与传统巨噬细胞不同，其 FXIIIa 和 CD34 表达的抗原异质性与其在真皮中的微解剖位置有关。此外，它们表达特殊的膜-基质斑块，这可能稳定它们在真皮各层中的位置。最后，真皮树突状细胞的浅表亚群与肥大细胞密切相关，并在肥大细胞脱颗粒时表现出增强的 FXIIIa 表达，这一事件似乎是由于肥大细胞肿瘤坏死因子在树突状细胞微环境中的释放所致。
这些新的见解将真皮树突状细胞确立为独特的固定皮肤细胞，具有肥大细胞依赖性促进纤维蛋白交联和基质重塑的潜在功能能力。因此，真皮树突状细胞这些以前未被认识的表型和功能特征可能与负责皮肤伤口愈合和止血的细胞相互作用有关。
